Pro-Taliban militants in Pakistan have threaded to launch retaliatory attacks on the US following the suspicious killing of al-Qaeda leader Osama bin Laden near Islamabad.

"We will avenge his death and launch attacks against American and Pakistani governments and their security forces," AFP quoted militants' spokesman Ehsanullah Ehsan as saying.

However, the spokesman noted that the militant group had not managed to confirm bin Laden's death.

Earlier, US President Barack Obama announced that bin Laden was killed in a military attack on a compound in northeastern Pakistan.

The United States accuses Bin Laden of having masterminded a number of terrorist operations, including the attacks on New York and Washington on September 11, 2001

Meanwhile, a US official says bin Laden's body has been buried at sea, alleging that his hasty burial was in accordance with Islamic law, which requires burial within 24 hours of death.

This is while burial at sea is not an Islamic practice and Islam does not determine a timeframe for burial.

The official added that finding a country willing to accept the remains of the world's most wanted man was difficult, so the US decided to bury him at sea.

Many believe bin Laden was killed years ago and his death was not announced to justify continued US military presence in Afghanistan. Others doubt that bin Laden has actually been killed, citing the precedence of US military announcing the death of other high-profile terrorists, who later were proven to be alive.